Using lodash to compare jagged arrays items existence without order

Question

I know I can do it using loops  but I m trying to find an elegant way of doing this  I have two jagged arrays  array of arrays   var array1      a    b      b    c     var array2      b    c      a    b      I want to use lodash to confirm that the above two jagged arrays are the same  By  the same  I mean that there is no item in array1 that is not contained in array2  Notice that the items in jagged array are actually arrays  So I want to compare between inner arrays  In terms of checking equality between these items    a    b        b    a     or   a    b        a    b     Both work since the letters will always be in order   UPDATE  Original question was talking about to  quot arrays quot   instead of jagged arrays  and for years many people discussed  and added answers  about comparing simple one-dimensional arrays  without noticing that the examples provided in the question were not actually similar to the simple one-dimensional arrays they were expecting

User · Answer

Edit  I missed the multi-dimensional aspect of this question  so I m leaving this here in case it helps people compare one-dimensional arrays  It s an old question  but I was having issues with the speed of using  sort   or sortBy    so I used this instead   function arraysContainSameStrings array1  string    array2  string     boolean     return       array1 length     array2 length  amp  amp      array1 every  str    gt  array2 includes str    amp  amp      array2 every  str    gt  array1 includes str           It was intended to fail fast  and for my purposes works fine

User · Answer

If you sort the outer array  you can use   isEqual   since the inner array is already sorted   var array1      a    b      b    c     var array2      b    c      a    b       isEqual array1 sort    array2 sort       true   Note that  sort   will mutate the arrays  If that s a problem for you  make a copy first using  for example   slice   or the spread operator         Or  do as Daniel Budick recommends in a comment below     isEqual   sortBy array1     sortBy array2     Lodash s sortBy   will not mutate the array

User · Answer

We can use   difference function to see if there is any difference or not  function isSame arrayOne  arrayTwo       var a     uniq arrayOne      b     uniq arrayTwo      return a length     b length  amp  amp               isEmpty   difference b sort    a sort            examples console log isSame  1  2  3    1  2  3        true console log isSame  1  2  4    1  2  3        false console log isSame  1  2    2  3  1        false console log isSame  2  3  1    1  2        false     Test cases pointed by Mariano Desanze  Thanks  console log isSame  1  2  3    1  2  2        false console log isSame  1  2  2    1  2  2        true console log isSame  1  2  2    1  2  3        false  I hope this will help you  Adding example link at StackBlitz

User · Answer

PURE JS  works also when arrays and subarrays has more than 2 elements with arbitrary order   If strings contains   use as join  -   parametr  character  can be utf  which is not used in strings  array1 map x  gt x sort    sort   join       array2 map x  gt x sort    sort   join      x000D   x000D  var array1      a    b      b    c     x000D  var array2      b    c      b    a     x000D   x000D  var r   array1 map x  gt x sort    sort   join       array2 map x  gt x sort    sort   join    x000D   x000D  console log r   x000D   x000D   x000D

User · Answer

There are already answers here  but here s my pure JS implementation  I m not sure if it s optimal  but it sure is transparent  readable  and simple      Does array a contain elements of array b  const contains    a  b    gt  new Set     a     b   size     a length const isEqualSet    a  b    gt  contains a  b   amp  amp  contains b  a    The rationale in contains   is that if a does contain all the elements of b  then putting them into the same set would not change the size   For example  if const a    1 2 3 4  and const b    1 2   then new Set     a     b        1 2 3 4   As you can see  the resulting set has the same elements as a    From there  to make it more concise  we can boil it down to the following   const isEqualSet    a  b    gt      const unionSize   new Set     a     b     return unionSize     a length  amp  amp  unionSize     b length

User · Answer

By  the same  I mean that there are is no item in array1 that is not contained in array2    You could use flatten   and difference   for this  which works well if you don t care if there are items in array2 that aren t in array1  It sounds like you re asking is array1 a subset of array2   var array1      a    b      b    c     var array2      b    c      a    b      function isSubset source  target        return    difference   flatten source     flatten target   length     isSubset array1  array2        true array1 push  d    isSubset array1  array2        false isSubset array2  array1        true

User · Answer

You can use lodashs xor for this  doArraysContainSameElements     xor arr1  arr2  length     0   If you consider array  1  1  to be different than array  1  then you may improve performance a bit like so   doArraysContainSameElements   arr1 length     arr2 length     0  amp  amp    xor arr1  arr2  length     0

[javascript] Using lodash to compare jagged arrays (items existence without order)

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